The design of fuzzy control system for food freezing temperature control

Abstract

Objective: Improving the setting value adjustment ability of the speed control loop and temperature control loop of food entering the freezing tunnel. Methods: By treating the speed and temperature control circuits of the conveyor belt separately, a fuzzy control system for food freezing temperature control was designed. The control system included a proportional-integral-differential controller for the food conveyor roller speed, a proportional-integral controller for temperature regulation in the freezing tunnel, and a Takagi-Sugeno fuzzy controller to set the temperature set point of the temperature regulation proportional-integral controller. Results: When the mass flow rate of frozen food was increased from 650 kg/h to 700 kg/h, and the speed of the drive roller being increased from 1.62 r/min to 1.75 r/min, the final food temperature could be quickly restored to about -18 ℃. When a temperature disturbance of +5 ℃occurred at the food inlet, the fuzzy controller acts to keep the food outlet temperature near the expected value of -18 ℃. In summary, by selecting system parameters that allow fast response and relatively low overshoot, the designed control system can realize that the value of the output variable does not fluctuate greatly near the set value. Conclusion: The research results can be used to develop the food freezing temperature control system in the food processing plant of the cryogenic freezing tunnel, and improve the ability of food freezing temperature control.

Keywords

• food freezing
• proportional-integral-differential control
• system identification
• fuzzy control
• takagi-sugeno control